The following image shows why 20-mph is the best speed while driving through built up areas and where we live, work and walk.
Chart showing stopping distances at 30mph and 20mph
| Distance from a driver noticing someone potentially in the path of their vehicle | Driver speed at 30mph
|
Driver speed at 20mph
|
| 0-6 metres | Likely to kill | Likely to injure |
| 6-12 metres | Likely to kill | Likely to hurt |
| 12-23 metres | Likely to seriously injure, less likely to kill | The driver stops without hitting the child. |